1. Technical Field
The present invention relates to a device that controls a power supply for charging a high-voltage battery mounted on a vehicle or driving an auxiliary machine incorporated in the vehicle.
2. Related Art
On an electric automobile or a hybrid car, the high-voltage battery that is a driving source for a running motor is mounted, and a battery charger for charging the high-voltage battery is provided. A low-voltage power generator is also provided in order to step down a voltage at the high-voltage battery to supply power to various in-vehicle devices (an auxiliary machine). For example, Japanese Unexamined Patent Publication Nos. 2009-27774, 2011-72069, and 2011-223833 each discloses vehicle power-supply control devices each of which includes the battery charger and the low-voltage power generator.
The device disclosed in Japanese Unexamined Patent Publication No. 2009-27774 includes a main electric storage device that can be charged from the outside of the vehicle, a voltage conversion device that steps down the voltage at the main electric storage device and outputs the step-down voltage, a sub-electric storage device that is charged by the voltage output from the voltage conversion device and supplies the power to an auxiliary machine load, and a control device that controls the voltage conversion device. The control device continuously drives the voltage conversion device during running of the vehicle, and the control device intermittently drives the voltage conversion device while the main electric storage device is charged.
The device disclosed in Japanese Unexamined Patent Publication No. 2011-72069 includes an auxiliary machine battery, an electric storage device that can be charged, and a charging device that charges the electric storage device using an AC power supplied from an external power supply. The charging device includes a control power supply that generates a controlling power-supply voltage used to control the charging device using the AC power supplied from the external power supply, an AC/DC converter, and a control device that controls the AC/DC converter. During the charge using the AC power from the external power supply, according to a charge state of the auxiliary machine battery, the control device charges the auxiliary machine battery using the controlling power-supply voltage generated by the control power supply.
The device disclosed in Japanese Unexamined Patent Publication No. 2011-223833 includes an electric storage device that can be charged using the power from the external power supply, an auxiliary machine battery that supplies the power supply voltage to the auxiliary machine load, a DC/DC converter that steps down the power from the electric storage device to supply the power supply voltage to the auxiliary machine load and the auxiliary machine battery, and an AC/DC converter that, using the power from the external power supply, can supply the power supply voltage to a charging ECU (Electronic Control Unit) and charge the auxiliary machine battery. During the charge using the power from the external power supply, one of the DC/DC converter and the AC/DC converter is selectively driven based on the charge state of the auxiliary machine battery and the state of the auxiliary machine load.
In the device including the battery charger for charging the high-voltage battery and the low-voltage power generator for driving the auxiliary machine, the number of components increases, when the controller that controls the battery charger and the controller that controls the low-voltage power generator are separately provided. Therefore, it is conceivable that the controller is shared by the battery charger and the low-voltage power generator. However, in this case, unfortunately the load on the controller increases.